Brazil- either Rio or Sao Paulo to Johannesburg
 

One way, what airline would you choose?
Don't have miles, it would be USD.
From what I'm seeing the choice of airlines would be slim.

There are only direct flights from São Paulo to Jo'burg (operated by SAA and Latam). From Rio you'd either have to connect in GRU or Luanda, since TAAG flies to Rio.

Latam is much cheaper on this route, leading to constant rumours that they will ditch the route due to low occupancy.

However, international one-way flights from Brazil usually book into Y fares, so it would be cheaper to buy a cheap return and dump the 2nd leg.

Case in point: for sample dates in Sept, both SAA and Latam cost around $1,000 one way, whereas a rtn on Latam is $550 and $1,000 on SAA.

Google flights can help you on the next steps.

Thank you for the info!

Something popped up on one of the blogs - GRU-LAD for £294 return on TAAG - June to August.